Known seating systems for wheelchairs allow the entire seat to pivot about a fixed point. In general, this fixed pivot point is positioned so as to coincide with the vertical center of mass of an individual sitting in the wheelchair. The result of tilting the seat about this fixed pivot point is that relatively little effort is required to rotate the individual. However, the problem with such an arrangement is that the user's knees moves significantly upward as the seat is tilted. Thus, in the tilted position of the seat, the user can not touch the ground with his feet, thereby preventing him to self-propel the wheelchair using his feet. Furthermore, the upward movement of the user's knees during the tilting of the wheelchair may be problematic when the wheelchair user is at a location with a limited freedom of movement for the knees, for instance underneath a table top.
For solving this problem, other known seating systems for wheelchairs are configured such that the fixed pivot point is positioned near the front of the seat. In this case, the distance from the knees to the ground does not vary significantly during the tilting of the wheelchair, thereby allowing the self-propelling of the wheelchair by the user with his feet in the tilted position of the seat. However, the problem with such an arrangement is that the back of the seat moves significantly downward as the seat is tilted. Thus, with such an arrangement, a risk potentially exists that the back of the seat hits the ground or a part of the frame as the seat is tilted. To avoid this problem, the seat must be sufficiently raised relative to the frame, leading to a significant increase of the total height of the wheelchair. Furthermore, because the center of gravity of the seat, and therefore of the user, is positioned behind the pivot point, a risk potentially exists that the user could fall backward as the seat is tilted.